Cup Plant

Silphium perfoliatum 
 
Imposing mature plants provide an unmistakable vertical presence in the garden. Thick stems perforate the cup-like united leaves. The large yellow flowers are borne on 1-foot stems at the tops of the plants. Hummingbirds and butterflies are attracted to the nectar, while the seeds are favorites of goldfinches. Historically, this plant was a general medicinal agent. Tolerant of clay soil and drought.